import java.util.Scanner;

public class Main {
    public static double Max3(int a,int b,int c){
        int max = a;
        if(max < b){
            max = b;
        }
        if(max < c){
            max = c;
        }
        return max*1.0;
    }

    public static void main(String[] args) {
        Scanner num = new Scanner(System.in);
        int x = num.nextInt();
        int y = num.nextInt();
        int z = num.nextInt();

        double m = Max3(x+y,y,z)/(Max3(x,y+z,z)+Max3(x,y,y+z));
        System.out.println(String.format("%.2f",m));
    }
}
